arithmetic-type/uint64

import {add64} from './add64.js';

/**
 * Multiplies two uint32 into one uint64.
 */
export const mul3264 = (a, b) => {
    const a0 = (a >>> 16) & 0xff_ff;
    const a1 = a & 0xff_ff;
    const b0 = (b >>> 16) & 0xff_ff;
    const b1 = b & 0xff_ff;

    const x = [Math.imul(a0, b0), Math.imul(a1, b1)];
    const t = Math.imul(a0, b1);
    const u = Math.imul(a1, b0);
    const y = [(t >>> 16) | 0, (t << 16) | 0];
    const z = [(u >>> 16) | 0, (u << 16) | 0];
    return add64(x, add64(y, z));
};